1. Field of the Invention
One or more embodiments of the present invention relate to a microphone disposed outside or inside a vehicle cabin, and particularly, to the structure of a waterproof microphone configured to prevent ingress of water or rubbish.
2. Description of the Related Art
As an use of a microphone installed outside a vehicle cabin, for example, PTL 1 discloses an example of a device in which a plurality of microphones are disposed outside a vehicle cabin to detect a travelling sound of another vehicle and a sound source direction of the another vehicle is estimated.
As a use of a microphone installed outside another vehicle cabin, for example, PTL 2 discloses an example of a vehicle voice recognition device that operates an in-vehicle control device through voice recognition using a contact type microphone (referred to as an NAM microphone) which is brought into contact with a human body and collects a voice spoken by a person. The structure of the NAM microphone of PTL 2 is disclosed in, for example, PTL 3, PTL 4, PTL 5, and PTL 6. As the related art, there is PTL 7 disclosing a timepiece microphone rather than a microphone for a vehicle use.
PTL 1 is Pamphlet of International Publication No. WO 2011/136234. PTL 2 is JP-A-2006-276605. PTL 3 is Japanese Patent No. 3760173. PTL4 is Japanese Patent No. 4671290. PTL 5 is Japanese Patent No. 4702795. PTL 6 is Japanese Patent No. 5203899. PTL 7 is JP-A-63-18289.